As existing tracts of wilderness become more and more fragmented, it is imperative to understand the space use of threatened wildlife species. Protected areas are essential to the preservation of large carnivores, but maintaining connectivity between these locations is key to the long-term persistence of these species. Further, the complex ecological relationships between top carnivore species within these constrained areas often leads to “winners” and “losers”, where the most dominant predators can suppress or even entirely displace more subordinate species.
These dominant-subordinate relationships between top predators are fascinating, and I am particularly interested in examining the space-use and conservation needs of subordinate large carnivores, particularly cheetahs in Africa and mountain lions in North America. Understanding how and why these wide-ranging species use the landscape will be a function of their relationship within the greater ecological community (e.g. their interactions with more dominant predators, or the abundance of their prey), as well as anthropogenic drivers such as habitat fragmentation and livestock conflict.
The use of competition refugia by mountain lions in the Southern Greater Yellowstone Ecosystem
Masters research: Pace University, Panthera’s Teton Cougar Project
Funded by the National Science Foundation, my masters research investigates resource selection by mountain lions in the Southern Greater Yellowstone Ecosystem, specifically looking at patterns of predation and the use of competition refugia by this subordinate species.
At present, my research is two-part: as part of the Teton Cougar Project (TCP) research team, I examined the landscape and microsite characteristics of mountain lion bed sites. After determining that bed sites do seem to function as competition refugia, I used a resource selection function (RSF) approach to create a map of the landscape that spatially projects the relative likelihood that a mountain lion would sleep in a given area. By comparing this “refugia” surface with a probability surface mapping relative prey availability, it will be possible to examine the relative importance of these contrasting resource requirements in mountain lion home range habitat selection.
In simpler terms, my research examines the trade-off that mountain lions must balance as subordinate predators. As a top carnivore, mountain lions must have access to food (i.e. prey). Typically, however, they are not the top-most predator in their ecosystem; bears steal their hard-earned kills, and wolves not only steal their food but also kill mountain lions and their kittens. This means that mountain lions can’t just spend all their time hunting and eating. They must also seek out safe places to sleep. This requirement for safe places is scientifically referred to as “refugia”. My thesis research uses known bed sites as a way to spatially measure mountain lion refugia, and known kill sites as a way to measure high-quality hunting habitat. I then use statistical models to create a landscape-level map that delineates areas of high and low quality refugia habitat and hunting habitat.
Why does this matter? Well, when many people think about conserving or managing large predators such as mountain lions, they typically focus on their food requirements (i.e. the availability of prey species like deer). Though this is definitely an important consideration, mountain lions must constantly manage a trade-off between finding food and staying safe. Because the best hunting habitats are not necessarily the safest places to sleep, a mountain lion must find a home range that can provide both types of environment. We hope that this new research will help scientists, managers, and conservationists to broaden their perspective when considering the kinds of habitats and landscapes mountain lions (and other subordinate predators) may need in order to make the best-possible conservation and management decisions.
The use of scent-marking trees by male cheetah in the Moremi Game Reserve, Botswana
Undergraduate research: Cornell University, Botswana Predator Conservation Trust
Scent-marking is the primary means of communication for many wide-ranging, solitary carnivore species. Cheetahs are one such example: they commonly use scent-marking trees (sometimes referred to as “play trees”) to communicate with their neighbors. Researchers often set cameras at the base of marking trees to determine the presence or relative abundance of cheetahs within in area. But even though we know that these features are ecologically important, we actually know very little about the role and function of marking trees in cheetah communication and social behavior. For example: How often they are used? Where they are located within a cheetah’s home range or territory? Does their use vary given where they are located within a territory? How often do neighboring male and female conspecifics visit them? Under the guidance of Dr. Femke Broekhuis and the Botswana Predator Conservation Trust, I examined the placement and use of scent-marking trees by a coalition of two male cheetahs in northwest Botswana. Though small in scope, my undergraduate research revealed new information about a commonly-used but poorly-understood aspect of cheetah ecology. Keep your eyes out for forthcoming publications!